Bioresource and Agricultural Engineering Commons^™

Agricultural Water Conservation And Efficiency In California - A Commentary, Charles M. Burt, Peter Canessa, Lawrence J. Schwankl, David F. Zoldoske

BioResource and Agricultural Engineering

This is a Commentary on some of the key points that are presented in “More with Less: Agricultural Water Conservation and Efficiency in California” by Cooley, ChristianSmith, and Gleick of the Pacific Institute, September 2008 (referred to as the “PacInst Paper” in the remainder of this discussion).

The authors of this Commentary have over 120 years combined of experience in agricultural and landscape irrigation. They have worked world-wide in design and installation of all types of irrigation systems (including automated drip systems from 1975 on), design and implementation of irrigation scheduling programs since 1977; design and implementation of water conservation …

Avoiding Common Problems With Drip Tape, Charles M. Burt

BioResource and Agricultural Engineering

This publication is meant to help farmers, dealers, and manufacturers recognize and understand some of the problems that have been experienced with drip tape – problems that are quite different from manufacturing defects. Problems that are quickly detected and properly identified can often be remedied, or be avoided in the future. The report addresses drip tape damage caused by pests, installation, emitter pressure, plugging, and other categories.

Exploring Potential U.S. Switchgrass Production For Lignocellulosic Ethanol, Ethan B. Davis, Henriette I. Jager, Tristram O. West, Robert D. Perlack, Craig C. Brandt, Stan D. Wullschleger, Latha M. Baskaran, Erin G. Wilkerson, Mark E. Downing, Carla A. Gunderson

United States Department of Energy: Publications

In response to concerns about oil dependency and the contributions of fossil fuel use to climatic change, the U.S. Department of Energy has begun a research initiative to make 20% of motor fuels biofuel based in 10 years, and make 30% of fuels bio-based by 2030. Fundamental to this objective is developing an understanding of feedstock dynamics of crops suitable for cellulosic ethanol production. This report focuses on switchgrass, reviewing the existing literature from field trials across the United States, and compiling it for the first time into a single database. Data available from the literature included cultivar and crop …

Technical Concepts Related To Conservation Of Irrigation And Rain Water In Agricultural Systems, A. J. Clemmens, R. G. Allen, Charles M. Burt

BioResource and Agricultural Engineering

Forty percent of freshwater withdrawals in the United States are for irrigated agriculture, which contribute more than $50 billion to the economy. Increasing diversions of water for urban, environmental, and other uses will likely decrease water available to agriculture. Water conservation in agriculture is touted as a good method for minimizing the impact of reduced agricultural diversions on production. Because “wasted” water is often reused until it reaches the ocean, there are limitations to the true water savings that result from programs that aim to increase irrigation efficiency. True water savings can come from four areas: reduction of unnecessary evaporation …

Facilitating Use Of The Odor Footprint Tool By Nebraska Pork Producers, Rick R. Stowell

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The goal of this project was to make Odor Footprint Tool (OFT) resources readily usable by pork producers and their technical advisors as a planning and screening tool when siting swine facilities. Detailed odor footprints for five specified sizes of swine facilities were developed for twenty-four locations throughout Nebraska: six regional sites and three “localized” sites within each region. Each odor footprint shows the predicted odor annoyance-free frequency as a function of the distance from the facility. Footprints developed using localized weather data differed only slightly from footprints produced using weather data from a regional site when the general topography …

Climate Models: An Assessment Of Strengths And Limitations, David Bader, Curt Covey, William Gutowski, Isaac Held, Kenneth Kunkel, Ronald Miller, Robin Tokmakian, Minghua Zhang

United States Department of Energy: Publications

Scientists extensively use mathematical models of Earth’s climate, executed on the most powerful computers available, to examine hypotheses about past and present-day climates. Development of climate models is fully consistent with approaches being taken in many other fields of science dealing with very complex systems. These climate simulations provide a framework within which enhanced understanding of climate-relevant processes, along with improved observations, are merged into coherent projections of future climate change. This report describes the models and their ability to simulate current climate.
The science of climate modeling has matured through finer spatial resolution, the inclusion of a greater number …

Accuracy Of Global Microirrigation Distribution Uniformity Estimates, Stuart W. Styles, Charles M. Burt, Franklin Gaudi, Sierra Layous

BioResource and Agricultural Engineering

Emitter pressures and flow rates were systematically and extensively sampled in one drip and one microspray field. The data distributions are presented. The accuracy of rapid (limited samples) evaluation pressure sampling procedures was found to be quite good if the pressure distribution was systematic, but erroneous if the pressure distribution throughout a field was random. A simple mathematical combination of two nonuniformity components (due to pressure differences, and other causes of flow variation) provided a better estimate of overall system distribution uniformity than more complex mathematics.

Conversion To Groundwater Pumping With Drip/Micro Irrigation Systems, Charles M. Burt, Monte Soto

BioResource and Agricultural Engineering

Twenty one irrigation districts in the Central Valley reported “conversion acres”. Conversion acres are those on which farmers used only groundwater for drip/micro irrigation although surface irrigation water was available.

The twenty one districts include about 2 million acres of irrigated area. Approximately 3.6% of that acreage (73,000 acres) has been “converted” to groundwater when farmers switched to drip/micro. Fourteen of these districts anticipate more conversion in the future. ITRC thinks that the conversion will be more rapid and greater than district personnel suspect.

The dominant factor that influences the conversion was the lack of flexible water delivery service to …

Sensor Ranging Technique For Determining Corn Plant Population, Joe D. Luck, Santosh Pitla, Scott A. Shearer

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Mapping of corn plant population can provide useful information for making field management decisions. This research focused on using low cost infra-red sensors to count plants. The voltage output data from the sensors were processed using an algorithm developed to extract plant populations. Preliminary investigations were conducted using sensors mounted on a stationary track for laboratory testing and on a row crop tractor for field testing. Repeated measurements were taken on a manually counted corn row. Visual inspection of the data from the field test indicated the potential to identify corn stalks based on approximate physical widths of the stalks. …

Automatic Guidance System Development Using Low Cost Ranging Devices, Santosh Pitla, Joe D. Luck, Scott A. Shearer

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Autonomous guidance of agricultural vehicles for various field operations serves to increase productivity. Low cost infra-red ranging devices were used in this study to estimate the guidance directrix (offset distance (d) and heading error angle (Ø)). Two kinds of tracks were used for evaluating the performance of the infra-red sensors, one track was made of a cardboard in the laboratory and the other track was made of wheat crop in the field. The cardboard track consisted of straight parallel and non parallel edges whereas the wheat crop track had a series of different edges including few curves. From the results …

Genome Sequencing And Analysis Of The Biomass-Degrading Fungus Trichoderma Reesei (Syn. Hypocrea Jecorina), Diego Martinez, Randy M. Berka, Bernard Henrissat, Markku Saloheimo, Mikko Arvas, Scott E. Baker, Jarod Chapman, Olga Chertkov, Pedro M. Coutinho, Dan Cullen, Etienne G. J. Danchin, Igor V. Grigoriev, Paul Harris, Melissa Jackson, Christian P. Kubicek, Cliff S. Han, Isaac Ho, Luis F. Larrondo, Alfredo Lopez De Leon, Jon K. Magnuson, Sandy Merino, Monica Misra, Beth Nelson, Nicholas Putnam, Barbara Robbertse, Asaf A. Salamov, Monika Schmoll, Astrid Terry, Nina Thayer, Ann Westerholm-Parvinen, Conrad L. Schoch, Jian Yao, Ravi Barabote, Mary Anne Nelson, Chris Detter, David Bruce, Cheryl R. Kuske, Gary Xie, Paul Richardson, Daniel S. Rokhsar, Susan M. Lucas, Edward M. Rubin, Nigel Dunn-Coleman, Michael Ward, Thomas Brettin

United States Department of Energy: Publications

Trichoderma reesei is the main industrial source of cellulases and hemicellulases used to depolymerize biomass to simple sugars that are converted to chemical intermediates and biofuels, such as ethanol. We assembled 89 scaffolds (sets of ordered and oriented contigs) to generate 34 Mbp of nearly contiguous T. reesei genome sequence comprising 9,129 predicted gene models. Unexpectedly, considering the industrial utility and effectiveness of the carbohydrate-active enzymes of T. reesei, its genome encodes fewer cellulases and hemicellulases than any other sequenced fungus able to hydrolyze plant cell wall polysaccharides. Many T. reesei genes encoding carbohydrate-active enzymes are distributed nonrandomly in …

Aquatic Bacteria Removal Using Carbon Nanotubes, Suvish Melanta

Biological and Agricultural Engineering Undergraduate Honors Theses

The purpose of this project is to explore the functionality of carbon nanotubes as a bacterial removal method, specifically towards water-borne bacterial pathogens in wastewater by utilizing its unique magnetic and bacteria-binding properties. The general protocol set for this research follows five steps: 1) Preparation of wastewater media, 2) preparation of CNT culture, 3) preparation of reaction mixture with CNTs for bacterial binding, 4) magnetic separation of bacteria-bound-CNT clusters and, 5) assessment of supernatant. The CNTs effectively removed bacterial contaminants in the wastewater (10%, v/v) after the sand filtration process from the Paul R. Noland Wastewater Facility at Fayetteville, Arkansas. …

Implementing Mass Nutrient Balance Procedures On Swine Production Facilities, Richard Koelsch, Alan Sutton

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Whole Farm Nutrient Balance (WFNB) approaches have been used to provide a measure of environmental performance (Aarts et al., 1992; Lanyon and Beegle, 1993; Klausner, 1995). Whole farm balance concepts are used as part of the Netherlands Mineral Accounting System public policy that includes compulsory mineral input and output reports from livestock farms and levies for excess imbalances (Jongbloed and Lenis, 1998). Procedures for measuring WFNB will be followed in measurements made on commercial swine facilities for 2006 and 2007. The conclusions developed based upon data from 13 for 2006 include:

• On average, the participating swine producers import 1.5 units …

Electric Motor Efficiency Under Variable Frequencies And Loads, Charles M. Burt, Xianshu Piao, Franklin Gaudi, Bryan Busch, N. F. N. Taufik

BioResource and Agricultural Engineering

This paper details a study performed by the Irrigation Training and Research Center to determine motor performances under varying speeds [induced by a variable frequency drives (VFD) controller] and loads. A further goal of the study was to provide sufficient information to designers so that they could estimate total pumping plant power usage with a VFD-controlled installation. Motors were tested with a VFD as well as across-the-line. On average, the relative efficiency of the electrical system with a VFD may be approximately 8% lower than the relative efficiency of a properly designed, full-load across-the-line system. If one considers actual field …

The Genome Of Laccaria Bicolor Provides Insights Into Mycorrhizal Symbiosis, F. Martin, A. Aerts, D. Ahren, A. Brun, E. G. J. Danchin, F. Duchaussoy, J. Gibon, A. Kohler, E. Lindquist, V. Pereda, A. Salamov, H. J. Shapiro, J. Wuyts, D. Blaudez, M. Buee, P. Brokstein, B. Canback, D. Cohen, P. E. Courty, P. M. Coutinho, C. Delaruelle, J. C. Detter, A. Deveau, S. Difazio, S. Duplessis, L. Fraissinet-Tachet, E. Lucic, P. Frey-Klett, C. Fourrey, I. Feussner, G. Gay, J. Grimwood, P. J. Hoegger, P. Jain, S. Kilaru, J. Labbe, Y. C. Lin, V. Legue, F. Le Tacon, R. Marmeisse, D. Melayah, B. Montanini, M. Muratet, U. Nehls, H. Niculita-Hirzel, M. P. Oudot-Le Secq, M. Peter, H. Quesneville, B. Rajashekar, M. Reich, N. Rouhier, J. Schmutz, T. Yin, M. Chalot, B. Henrissat, U. Kues, S. Lucas, Y. Van De Peer, G. K. Podila, A. Polle, P. J. Pukkila, P. M. Richardson, P. Rouze, I. R. Sanders, J. E. Stajich, A. Tunlid, G. Tuskan, I. V. Grigoriev

United States Department of Energy: Publications

Mycorrhizal symbioses—the union of roots and soil fungi—are universal in terrestrial ecosystems and may have been fundamental to land colonization by plants. Boreal, temperate and montane forests all depend on ectomycorrhizae. Identification of the primary factors that regulate symbiotic development and metabolic activity will therefore open the door to understanding the role of ectomycorrhizae in plant development and physiology, allowing the full ecological significance of this symbiosis to be explored. Here we report the genome sequence of the ectomycorrhizal basidiomycete Laccaria bicolor (Fig. 1) and highlight gene sets involved in rhizosphere colonization and symbiosis. This 65-megabase genome assembly contains ~20,000 …

Effects Of Climate Change On Energy Production And Use In The United States, Thomas Wilbanks, Vatsal Bhatt, Daniel Bilello, Stanley Bull, James Ekmann, William Horak, Y. Joe Huang, Mark D. Levine, Michael J. Sale, David Schmalzer, Michael J. Scott

United States Department of Energy: Publications

Climate change is expected to have noticeable effects in the United States: a rise in average temperatures in most regions, changes in precipitation amounts and seasonal patterns in many regions, changes in the intensity and pattern of extreme weather events, and sea level rise. Some of these effects have clear implications for energy production and use. For instance, average warming can be expected to increase energy requirements for cooling and reduce energy requirements for warming. Changes in precipitation could affect prospects for hydropower, positively or negatively. Increases in storm intensity could threaten further disruptions of the sorts experienced in 2005 …

Biofuel Feedstock Assessment For Selected Countries, Keith L. Kline, Gbadebo A. Oladosu, Amy K. Wolfe, Robert D. Perlack, Virginia H. Dale, Matthew J. Mcmahon

Economics & Finance Faculty Publications

Findings from biofuel feedstock production assessments and projections of future supply are presented and discussed. The report aims to improve capabilities to assess the degree to which imported biofuel could contribute to meeting future U.S. targets to reduce dependence on imported oil. The study scope was focused to meet time and resource requirements. A screening process identified Argentina, Brazil, Canada, China, Colombia, India, Mexico, and the Caribbean Basin Initiative (CBI) region for initial analysis, given their likely role in future feedstock supply relevant to U.S. markets. Supply curves for selected feedstocks in these countries are projected for 2012, 2017 and …

Simulated Effects Of Reflective Mulch On Energy And Water Conservation In Semi-Arid Central California Greenhouses, T. Mehlitz, Ilhami Yildiz, S. Rahman, C. Hardin

BioResource and Agricultural Engineering

In addition to the labor, energy and water consumption are the two main cost drivers in current greenhouse systems. Consequently, considerable effort is expended to conserve energy and water, and look for alternative energy sources. Greenhouses in hot and arid regions also require large quantities of water for irrigation. Proper environmental management systems can significantly change the energy and moisture dynamics of greenhouse production systems. This study aims to focus on reducing energy and water consumption in semi-arid California greenhouses. Influences of mulch (having different reflectivities) on energy and water conservation were investigated. The reflectivity of mulch used as a …

Simulated Effects Of Various Environmental Management Practices On Energy Consumption In Open And Confined Greenhouse Systems, Ilhami Yildiz, D. P. Stombaugh

BioResource and Agricultural Engineering

The objective of this study was to evaluate the effects of relative humidity, light management levels, minimum ventilation rates, CO₂ enrichment and canopy size on energy consumption in three different greenhouse systems (conventional, open-loop heat pump, and confined heat pump) in winter, spring, and summer months. No difference was observed in energy consumption with relative humidity set point levels in winter due to the already low relative humidity levels. Some differences were observed in spring and summer due to extra dehumidification required to maintain the inside relative humidity at lower levels. Energy consumption in summer was reduced up to …

Irrigation District Energy Survey, Charles M. Burt, Daniel J. Howes

BioResource and Agricultural Engineering

This survey was completed by ITRC on behalf of the California Energy Commission Public Interest Energy Research (PIER) Program. The purpose of the survey was to establish a benchmark for the present status of the pumping systems used by agricultural water districts in California and to determine the districts' needs. The needs discussed involve technical assistance, research grant and low-interest loan funding, and district-related policy issues. Thirty agricultural water districts were selected for the survey. These districts were selected based on energy use per acre of irrigated area, size, geographic location, and distribution infrastructure.

The Role Of Multihaem Cytochromes In The Respiration Of Nitrite In Escherichia Coli And Fe(Iii) In Shewanella Oneidensis, Thomas A. Clarke, Tracey Holley, Robert S. Hartshorne, James K. Fredrickson, John M. Zachara, Liang Shi, David J. Richardson

United States Department of Energy: Publications

The periplasmic nitrite reductase system from Escherichia coli and the extracellular Fe (III) reductase system from Shewanella oneidensis contain multihaem c-type cytochromes as electron carriers and terminal reductases. The position and orientation of the haem cofactors in multihaem cytochromes from different bacteria often show significant conservation despite different arrangements of the polypeptide chain. We propose that the decahaem cytochromes of the iron reductase system MtrA, MtrC and OmcA comprise pentahaem ‘modules’ similar to the electron donor protein, NrfB, from E. coli. To demonstrate this, we have isolated and characterized the N-terminal pentahaem module of MtrA by preparing a …

Significant Redistribution Of Ce 4D Oscillator Strength Observed In Photoionization Of Endohedral Ce@C+82 Ions, A. M. Müller, S. Schippers, M. Habibi, D. A. Esteves, J. C. Wang, R. A. Phaneuf, A. L. D. Kilcoyne, A. Aguilar, L. Dunsch

United States Department of Energy: Publications

Mass-selected beams of atomic Ce^q+ ions (q = 2, 3, 4), of C⁺₈₂ and of endohedral Ce@C⁺₈₂ ions were employed to study photoionization of free and encaged cerium atoms. The Ce 4d inner-shell contributions to single and double ionization of the endohedral Ce@C⁺₈₂ fullerene have been extracted from the data and compared with expectations based on theory and the experiments with atomic Ce ions. Dramatic reduction and redistribution of the ionization contributions to 4d photoabsorption is observed. More than half of the Ce 4d oscillator strength appears to be …

Characterization Of Aerosols Containing Zn, Pb, And Cl From An Industrial Region Of Mexico City, Ryan C. Moffet, Yury Desyaterik, Rebecca J. Hopkins, Alexei V. Tivanski, Mary K. Gilles, Y. Wang, V. Shuthanandan, Luisa T. Molina, Rodrigo Gonzalez Abraham, Kirsten S. Johnson, Violeta Mugica, Mario J. Molina, Alexander Laskin, Kimberly A. Prather

United States Department of Energy: Publications

Recent ice core measurements show lead concentrations increasing since 1970, suggesting new non automobile-related sources of Pb are becoming important worldwide (1). Developing a full understanding of the major sources of Pb and other metals is critical to controlling these emissions. During the March, 2006 MILAGRO campaign, single particle measurements in Mexico City revealed the frequent appearance of particles internally mixed with Zn, Pb, Cl, and P. Pb concentrations were as high as 1.14 μg/m3 in PM₁₀ and 0.76 μg/m3 in PM_2.5. Real time measurements were used to select time periods of interest …

Assignment Of Polarization-Dependent Peaks In Carbon K-Edge Spectra From Biogenic And Geologic Aragonite, Dong Zhou, Rebecca A. Metzler, Tolek Tyliszczak, Jinghua Guo, Mike Abrecht, Susan N. Coppersmith, P. U. P. A. Gilbert

United States Department of Energy: Publications

Many biominerals, including mollusk and echinoderm shells, avian eggshells, modern and fossil bacterial sediments, planktonic coccolithophores, and foraminifera, contain carbonates in the form of biogenic aragonite or calcite. Here we analyze biogenic and geologic aragonite using different kinds of surface- and bulksensitive X-ray absorption near-edge structure (XANES) spectroscopy at the carbon K-edge, as well as highresolution scanning transmission X-ray microscopy (STXM). Besides the well-known main π* and σ* carbonate peaks, we observed and fully characterized four minor peaks, at energies between the main π* and σ* peaks. As expected, the main peaks are similar in geologic …

Challenges In Earth System Modelling: Approaches And Applications, D.J. Erickson Ill, Robert J. Oglesby, S. Elliott, W. Steffen, G. Brasseur

United States Department of Energy: Publications

Earth system modelling has taken on increasing importance over the past several years. These models are being used to address an increasing number of environmental and global change problems of societal concern (e.g. Adams et al., 1998; Easterling et al., 2000; Foley et al., 2003). Perhaps most commonly known is the application to possible greenhouse-gas induced warming (Hoffman et al., 2005). Other compelling problems include the climatic effects of land use changes, aerosols (including sulphate emissions, and smoke from biomass burning; Erickson et al., 1995; Oglesby et al., 1999), changing trace gas fluxes, interactions and feedbacks with the global carbon …

Understanding The Grafting Of Telechelic Polymers On A Solid Substrate To Form Loops, Zhenyu Huang, Haining Ji, Jimmy W. Mays, Mark D. Dadmun

United States Department of Energy: Publications

Recent experimental and theoretical studies have demonstrated that relative to singly tethered chains, the presence of polymer loops at interfaces significantly improves interfacial properties such as adhesion, friction, and wettability. In the present study, a simple system was studied to examine the formation of polymeric loops on a solid surface, where the grafting of carboxylic acid terminated telechelic polystyrene from the melt to an epoxy functionalized silicon is chosen. The impact of telechelic molecular weight, grafting temperature, and surface functionality on the telechelic attachment process is studied. It was found that grafting of the telechelic to the surface at both …

Synthesis And Characterization Of An Abc Miktoarm Star Terpolymer Of Cyclohexadiene, Styrene, And 2-Vinylpyridine, David Uhrig, Kunlun Hong, Jimmy W. Mays, S. Michael Kilbey Ii, Phillip F. Britt

United States Department of Energy: Publications

Several research groups have expended great effort toward the preparation of miktoarm (mixed-arm) star copolymers and terpolymers. We describe herein a novel synthesis, using anionicpolymerization,ofapoly(cyclohexadiene)[PCHD]-polystyrene [PS]-poly(2-vinylpyridine) [P2VP] miktoarm star terpolymer.

Previously, miktoarm A₂B and A₃B star polydiene copolymers comprised partially of poly(cyclohexadiene) have been synthesized by Tsoukatos and Hadjichristidis by employing chlorosilane linking techniques. More recently, an ABC star terpolymer of PS, polyisoprene, and PCHD was prepared by Yang and co-workers by using meta-double-diphenylethylene-based linking chemistry.

Small Angle Neutron Scattering Study Of Conformation Of Oligo(Ethylene Glycol)-Grafted Polystyrene In Dilute Solutions: Effect Of The Backbone Length, Gang Cheng, Yuri B. Melnichenko, George D. Wignall, Fengjun Hua, Kunlun Hong, Jimmy W. Mays

United States Department of Energy: Publications

The conformation and clusterization of comblike polymers of polystyrene densely grafted with oligo(ethylene glycol) (OEG) side chains in 1.0 wt % solutions of D₂O, toluene-d₈, and methanol-d₄ was investigated as a function of the degree of polymerization (DP) of the backbone by small angle neutron scattering (SANS). Each side chain had four EG repeat units, and the DP of the polystyrene backbone varied from 8 to 85. The global conformation of the polymers in toluene and methanol was shown to assume ellipsoidal, rigid cylindrical, or wormlike morphologies with increasing DP of the polystyrene …

A New Fluorinated Polymer Having Two Connected Rings In The Main Chain: Synthesis And Characterization Of Fluorinated Poly(1,3-Cyclohexadiene), Tianzi Huang, Jamie M. Messman, Jimmy W. Mays

United States Department of Energy: Publications

The high electronegativity and small size of the fluorine atom and the high stability of C-F bonds impart interesting properties and applications to fluorine containing polymers. The unique properties of fluoropolymers include high thermal stability, improved chemical resistance, low surface energies, low coefficients of friction, and low dielectric constants. Applications of fluorinated polymers include use as noncorrosive materials, polymer processing aids, chemically resistant and antifouling coatings, as well as interlayer dielectrics. Fluorine-containing polymers can be directly synthesized via polymerization of fluorine-containing monomers or by post-polymerization modification. The latter method can be used to attach fluorinated species, such as perfluoroalkyl groups, …

Impact Of Solvent Quality On The Density Profiles Of Looped Triblock Copolymer Brushes By Neutron Reflectivity Measurements, Zhenyu Huang, Jose Alonzo, Ming Liu, Haining Ji, Fang Yin, Grant D. Smith, Jimmy W. Mays, S. Michael Kilbey Ii, Mark D. Dadmun

United States Department of Energy: Publications

Preferential adsorption of poly(2-vinylpyridine)-deuterated polystyrene-poly(2-vinylpyridine) (PVP-dPS-PVP) triblock copolymers from toluene onto silicon leads to the formation of dPS loops tethered by the PVP end blocks. Using neutron reflectometry, we have determined the segment density profiles of these looped polymer brushes in toluene, a good solvent for the dPS block, and in cyclohexane at 20 °C (poor solvent), 32 °C, (near-Θ solvent), and 50 °C (marginal solvent). While the swelling behavior qualitatively agrees with that observed for singly grafted brushes, there are interesting differences in the local structural details: In a good solvent, the segment density profiles are composed of an …